Exhaust gas analyzing apparatus

Abstract

An exhaust gas analyzing apparatus of a vehicle mounted type equipped with an analyzer that is configured to analyze components contained in exhaust gas includes a sampling line that is an exhaust gas flow path extending from an exhaust gas introduction terminal that is configured to introduce the exhaust gas from the outside to the analyzer; a pressure reduction source that is configured to reduce a pressure in the sampling line to a predetermined pressure; and a temperature-regulating mechanism that is configured to regulate a temperature of the exhaust gas flowing in the sampling line to be at least a first temperature. The first temperature is set to be a temperature equal to or higher than an evaporation temperature of moisture at the reduced predetermined pressure and lower than an evaporation temperature of moisture at one atmospheric pressure.

What is claimed is: 
     
       1. An exhaust gas analyzing apparatus of a vehicle mounted type equipped with one or multiple analyzers that are configured to analyze components contained in exhaust gas, comprising:
 an exhaust gas introduction terminal that is connected to a hot hose; 
 a sampling line that is an exhaust gas flow path extending from the exhaust gas introduction terminal that is configured to introduce the exhaust gas from the outside to the one or multiples analyzers; 
 a single pressure reduction source that is arranged downstream of the one or multiple analyzers and that is configured to reduce a pressure in the sampling line to a predetermined pressure; 
 a pressure sensor that is arranged between the one or multiple analyzers and pressure reduction source; and 
 a temperature-regulating mechanism that is configured to
 regulate a temperature of the exhaust gas flowing in the sampling line to be at least a first temperature during normal analysis of the exhaust gas, and 
 regulate the temperature of the exhaust gas to be at least a second temperature greater than the first temperature during cold start operation of the vehicle prior to the normal analysis of the exhaust gas, 
 
 wherein the first temperature is set to be a temperature equal to or greater than an evaporation temperature of moisture at a reduced predetermined pressure and lower than an evaporation temperature of moisture at one atmospheric pressure. 
 
     
     
       2. The exhaust gas analyzing apparatus according to  claim 1 , wherein the temperature-regulating mechanism is equipped with a heating wire heater that is configured to regulate a temperature of the sampling line and a temperature setting part that is configured to set a set temperature which is a target value to be set to the heating wire heater, and wherein
 the temperature setting part is configured to change the set temperature in accordance with an atmospheric pressure. 
 
     
     
       3. The exhaust gas analyzing apparatus according to  claim 2 , wherein the temperature setting part is configured to change the set temperature in accordance with a type of an internal combustion engine of the vehicle. 
     
     
       4. The exhaust gas analyzing apparatus according to  claim 2 , wherein the one or multiple analyzers are adapted to analyze a concentration of moisture contained in the exhaust gas, and wherein
 the temperature setting part is configured to change the set temperature in accordance with an indication value of the one or multiple analyzers. 
 
     
     
       5. The exhaust gas analyzing apparatus according to  claim 1 , wherein the temperature-regulating mechanism is configured to change the temperature based on a pressure value that is measured by the pressure sensor. 
     
     
       6. The exhaust gas analyzing apparatus according to  claim 1  further comprising:
 one or multiple capillaries provided in an inlet side flow path or an outlet side flow path of the one or multiple analyzers. 
 
     
     
       7. The exhaust gas analyzing apparatus according to  claim 6 , wherein,
 the multiple analyzers include: 
 a CO CO2 analyzer that is adapted to analyze a concentration of CO or CO2 contained in the exhaust gas; and 
 a NOx analyzer that is adapted to analyze a concentration of NOx contained in the exhaust gas; and 
 the multiple capillaries include: 
 a first capillary that is provided between an outlet side of the CO CO2 analyzer and the reduction source; and 
 a second capillary that is provided in an inlet side of the NOx analyzer. 
 
     
     
       8. The exhaust gas analyzing apparatus according to  claim 7 , wherein,
 the multiple analyzers further include: 
 a THC analyzer that is adapted to analyzer a concentration of THC contained in the exhaust gas; and 
 the multiple capillaries further include: 
 a third capillary that is provided in an inlet side of the THC analyzer. 
 
     
     
       9. The exhaust gas analyzing apparatus according to  claim 8 , wherein,
 the multiple capillaries further include: 
 a fourth capillary that is provided between the exhaust gas introduction terminal and the THC analyzer. 
 
     
     
       10. The exhaust gas analyzing apparatus according to  claim 7 , wherein,
 the multiple capillaries further include: 
 a fifth capillary that is provided between the exhaust gas introduction terminal and the CO CO2 analyzer or the NOx analyzer. 
 
     
     
       11. An exhaust gas analyzing method using an exhaust gas analyzing apparatus of a vehicle mounted type equipped with one or multiple analyzers that are configured to analyze components contained in exhaust gas, wherein the exhaust gas analyzing apparatus includes an exhaust gas introduction terminal that is connected to a hot hose, a sampling line that is an exhaust gas flow path extending from the exhaust gas introduction terminal and that is configured to introduce the exhaust gas from the outside to the one or multiple analyzers, a single pressure reduction source that is arranged downstream of the one or multiple analyzers and that is configured to reduce a pressure in the sampling line to a predetermined pressure, a pressures sensor that is arranged between the one or multiple analyzers and pressure reduction source, and a temperature-regulating mechanism, the method comprising:
 regulating via the temperature-regulating mechanism a temperature of the exhaust gas flowing in the sampling line to be at least a first temperature, equal to or greater than an evaporation temperature of moisture at a reduced predetermined pressure and lower than an evaporation temperature of moisture at one atmospheric pressure, during normal analysis of the exhaust gas, and 
 regulating via the temperature-regulating mechanism the temperature of the exhaust gas flowing in the sampling line to be at least a second temperature greater than the first temperature during cold start operation of a vehicle prior to the normal analysis of the exhaust gas.